Russia And Italy Good And Bad

For potential buyer at a coin show, these sort of fakes are difficult to expose for what they are,
if that individual does not carry a micrometer screw gauge and a scales accurate to .01 of a gram.

It is only when they are examined at home with proper equipment and a good quality loupe for visual comparison with genuine, and reference on a data base with known fakes that a potential fraud can be exposed.

Also is a worry that an honest dealer,
when buying for inventory, does these sorts of checks on every coin he buys. Such a policy would be impracticable.
Probably only worth doing on coins with a potential resale value of more than $1000, and leave authentication to lower valued coins to the third party graders.

Although there is a remedy allowance for Weight Tolerance,(depending on the coin, as nominated by the Mint),
most coin catalogs list the nominal weight in grams to 2 decimal places.

The coins illustrated in grams to 2 decimal places, which is what you would normally expect and hope to see, when giving a weight for discussion, as in this thread.
Weight Tolerances which may be only a small fraction of a gram, can then be more accurately compared with a coin under discussion.
In a discussion such as in this thread, it is the weight difference compared to genuine that is important, and not so much the total weight of the coin.

My collection is a mix of coins made with intent to cheat one group or another.
The Russian coin was made to fool a merchant or someone in commerce.
So I doubt the present day catalog value would have any part of the equation.
The Italian coin may have been made to fool collectors.